"That program is buggy" is the oft-heard phrase used to describe a computer program that isn't working right. Oddly enough, the phrase originates from the days when computers worked by way of on-and-off mechanical relays. The very first computer bug mistakenly crawled into one of those relays and met its maker when the relay slammed into the closed position. Since the relay could no longer complete a circuit, the computer malfunctioned. The hapless computer bug was discovered during troubleshooting, and the name stuck. Today, computers have come a long way from relays, and are an integral part of everything from toasters to automobiles. But wait a minute; what the heck does this have to do with fuel injection?
Modern vehicles get their fuel by way of fuel injectors. The fuel injector is similar to those old relays in the sense that it pulses on, and off, to meter the correct amount of fuel into your engine. It performs this task by way of signals that come from the engine control unit computer, or ECU. The ECU monitors various sensors and tells the fuel injectors when and how much fuel to shoot into the engine according to the data input. Vroom-off you go. Without this electronic pulse, the injector doesn't know what to do, and might shoot too much, too little, or no fuel at all into it's respective cylinder. A rough running engine, loss of power, or poor engine idle may be indicators of fuel injector or fuel injector signal trouble.
Just like the relay in that early proto computer, the injector is fed an electronic signal through a set of wires. These wires stay put on the injector by way of a connector. Over time the contacts in the connector can become corroded, oxidized, or loose, and the pulses that tell the fuel injector when to fire the fuel into the cylinders may not get through. The injector connectors are just as susceptible to wear and tear as everything else in the engine compartment due to extremes in temperature. The good news is that while injectors are expensive, injector connectors can be had on the cheap and are easily replaced. When troubleshooting any system it's always a good idea to suspect the cheap stuff that wears out first. If your injector connectors show signs of cracking or wear, take time out to swap in some new ones for improved performance.